kaolinite and mica

Several inhaled substances, from occupational or other environmental exposure, produce significant pulmonary disease and abnormalities demonstrated by pulmonary imaging. Areas of controversy and misconception relate principally to the extent and nature of both the clinical disease and the imaging abnormalities specific to each substance. The size and shape of the inhaled particles is an important determinant of the nature and severity of the disease produced, with fibrous shapes usually being the most pathogenetic. Fibrogenicity is another important pathogenetic characteristic of talc and kaolin, as well as asbestos. Talc produces four distinct forms of pulmonary disease, depending not only on the other substances with which it is inhaled, but also whether it is inhaled or injected intravenously. When inhaled alone, talc does not appear to produce significant pulmonary fibrosis or malignancy. Kaolin, mica, fuller's earth, zeolite, and fiberglass all vary in disease production according to their shape and fibrogenicity. Silica, diatomaceous earth, and other forms of silica are all highly fibrogenic and thus produce clinically obvious disease with sufficient inhalation. The largest particles usually produce nodular patterns in the upper pulmonary fields, as is typical of silicosis. The fibrous particles are more likely to manifest themselves as interstitial patterns in the lower pulmonary fields.

Topics: Aluminum Silicates; Humans; Kaolin; Radiography; Silicon Dioxide; Silicosis; Talc; Zeolites

Topics: Aluminum Silicates; Animals; Asbestos; Coal; Dust; Humans; Kaolin; Metals; Pulmonary Fibrosis; Silicon Dioxide; Talc

Glitters are primary microplastics which are directly littered into the environment, yet the ecological effects have seldom been tested. When microplastics enter the environment, their physical presence and chemical leachate may alter the physiology of primary producers. Glitter can be composed of plastic or natural and/or biodegradable materials, often with additives. Three experiments were run for 14 days to separate chemical and physical effects of different types of glitter: polyethylene terephthalate (PET), biodegradable modified regenerated cellulose (MRC), synthetic mica, and a natural particle control (kaolinite) on several physical characteristics of Lemna minor (common duckweed). L. minor was exposed to either fresh (chemical and physical effects), leachate from glitter (chemical) or aged glitter (physical). Overall, there was little effect of PET, synthetic mica, kaolinite or of any aged glitter. High concentrations of fresh MRC glitters, however, decreased root length, biomass and chlorophyll content of L. minor. Some of these effects were also present when exposed to leachate from MRC glitters, but were less pronounced. Elemental analysis revealed the presence of metals in MRC glitters which may explain these responses. Short-term ecotoxicity of biodegradable glitters can arise due to their physical and chemical properties, but may lessen over time as their surface coating degrades.

Topics: Araceae; Fresh Water; Kaolin; Microplastics; Plastics; Polyethylene Terephthalates; Water Pollutants, Chemical

Because pressure generated by a displacement cord may traumatize the gingiva, cordless gingival displacement materials are available to the clinician as atraumatic alternatives. However, whether the pressures produced by the different systems are equivalent is unclear.. The purpose of this study was to investigate the pressures generated by 4 different cordless gingival displacement materials.. A chamber with a dimension of 5 × 5 × 2 mm was made from Type IV stone and silicone material to simulate a rigid and elastic environment. A pressure gauge was embedded into the wall of the chamber, and 4 materials (Expasyl, Expasyl New, 3M ESPE Astringent Retraction Paste, and Magic FoamCord) were injected into the chamber. The maximum and postinjection pressures were recorded with Chart 5 software and the Power Lab system. The pressures generated by the different materials were compared with a post hoc Mann-Whitney U test (α=.05).. The median postinjection pressures generated by Expasyl (142.2 kPa) and Expasyl New (127.6 kPa) were significantly greater than the pressures generated by 3M ESPE Astringent Retraction Paste (58.8 kPa) and Magic Foam Cord (32.8 kPa). Expasyl generated a maximum pressure of 317.4 kPa and Expasyl New of 296.6 kPa during injection, whereas 3M ESPE Astringent Retraction Paste generated 111.0 kPa, and Magic Foam Cord generated 17.8 kPa.. All cordless systems produced atraumatic pressures, with Expasyl New and Expasyl generating the highest pressures and, therefore, can be considered the most effective material.

Topics: Aluminum Chloride; Aluminum Compounds; Aluminum Silicates; Astringents; Chlorides; Dental Materials; Dimethylpolysiloxanes; Elasticity; Gingiva; Gingival Retraction Techniques; Humans; Kaolin; Materials Testing; Models, Anatomic; Polyvinyls; Pressure; Silicone Elastomers; Siloxanes

The coagulation behavior of Al(13) aggregates formed in coagulation of kaolin was investigated by small angle static light scattering (SASLS), solid-state (27)Al NMR and tapping mode atomic force microscope (TM-AFM). A kaolin suspension was coagulated by PACl containing high content of Al(13) polycation (PACl-Al(13)). The results indicated that Al(13) was predominant in destabilizing kaolin particles for PACl-Al(13) coagulation even though at alkaline pH (pH 10). At such high pH, Al(13) aggregates were observed when the dosage of PACl-Al(13) was increased. In addition, the mechanism of coagulation by PACl-Al(13) at alkaline pH was affected by dosage. When the dosage was insufficient, coagulation was caused by electrostatic patch, which led to compact flocs with high fractal dimension (D(f)). Interparticle bridging dominated the coagulation when the coagulant dosage approached the plateau of adsorption, which caused the looser flocs with low D(f). The in-situ AFM scanning in liquid system proved that the existence of linear Al(13) aggregates composed of a chain of coiled Al(13) in coagulation by PACl-Al(13) at a high dosage and alkaline pH. Meanwhile, several coiled Al(13) aggregates with various dimensions were observed at such condition.

Topics: Adsorption; Aluminum; Aluminum Silicates; Hydrogen-Ion Concentration; Kaolin; Magnetic Resonance Spectroscopy; Microscopy, Electron, Scanning; Water Pollutants, Chemical

There is a need to develop highly CU2+ selective materials which can potentially remediate copper contaminated soils and water. Here we show that several highly charged synthetic swelling mica-type clays are highly selective for copper exchange. The synthetic micas have cation exchange capacities (CECs), which are close to their theoretical values. Both Na-saturated and Mg-saturated micas were investigated for Cu ion exchange selectivity. Ion exchange isotherms and Kielland plots were constructed using the equilibrated solution analyses. From these studies it was found that Na-4-mica and Na-3-mica could selectively exchange copper at lower concentrations from solution, whereas Na-2-mica sample performed better by showing Cu ion exchange selectively to almost its capacity. The EPR spectra of Cu-exchanged micas coincide with the mica's charge characteristics that predict increased binding strength of exchangeable Cu in Na-4-mica and Na-3-mica than in Na-2-mica.

Topics: Aluminum Silicates; Clay; Copper; Fluorides; Ion Exchange; Kaolin; Magnesium Chloride; Magnesium Compounds; Silica Gel; Silicon Dioxide; Sodium Chloride; Soil Pollutants; Waste Management

Knowledge of sorption and desorption of heavy metals by individual soil components should be useful for modelling the behaviour of soils of arbitrary composition when contaminated by heavy metals, and for designing amendments increasing the fixation of heavy metals by soils polluted by these species. In this study the competitive sorption and desorption of Cd, Cr, Cu, Ni, Pb and Zn by humified organic matter, Fe and Mn oxides, kaolinite, vermiculite and mica were investigated. Due to the homogeneity of the sorbents, between-metal competition for binding sites led to their preferences for one or another metal being much more manifest than in the case of whole soils. On the basis of k(d100) values (distribution coefficients calculated in sorption-desorption experiments in which the initial sorption solution contained 100mgL(-1) of each metal), kaolinite and mica preferentially sorbed and retained chromium; vermiculite, copper and zinc; HOM, Fe oxide and Mn oxide, lead (HOM and Mn oxide also sorbed and retained considerable amounts of copper). Mica only retained sorbed chromium, Fe oxide sorbed cadmium and lead, and kaolinite did not retain sorbed copper. The sorbents retaining the greatest proportions of sorbed metals were vermiculite and Mn oxide, but the ratios of k(d100) values for retention and sorption suggest that cations were least reversibly bound by Mn oxide, and most reversibly by vermiculite.

Topics: Adsorption; Aluminum Silicates; Binding, Competitive; Kaolin; Manganese Compounds; Metals, Heavy; Oxides; Soil

Seventeen cases of "talc pneumoconiosis" were examined pathologically and mineralogically to ascertain whether a true talc pneumoconiosis existed and also to compare these results in primary, secondary, and tertiary exposures. Mineralogic analyses were performed on wet tissue or tissue blocks by a variety of techniques, including analytical transmission electron microscopy and x-ray diffraction. Overall, the pathologic appearance of the tissues was similar in primary, secondary, and tertiary exposures, although ferruginous bodies and foreign body giant cells were not always present in cases caused by secondary exposures. Mixed dust fibrotic lesions were found in two cases in which there were substantial quantities of quartz present. There was great variation in the minerals found within the lung tissues. Several cases showed significant quantities of mica and kaolin in addition to talc. One case consisted predominantly of mica and in fact could be regarded as "mica pneumoconiosis"; this diagnosis was correctly attributed because of the mineralogic findings. Tremolite fibers were found in only two cases. Substantial quantities of crocidolite and amosite fibers were found in one case. This study shows that "talcosis" frequently represents disease associated with a variety of minerals and that talc is a common denominator. It shows also the usefulness of lung dust mineral analysis, particularly in secondary industries, for evaluating the cause of a pathologic reaction when exposures are especially complex.

Topics: Aged; Aluminum Silicates; Female; Humans; Kaolin; Lung; Male; Microscopy, Electron; Middle Aged; Pneumoconiosis; Talc; X-Ray Diffraction

Fourier transform i.r. measurements of L-pyroglutamic acid dispersed in a matrix of a clay, silica or alumina have been obtained at various temperatures between 25 and 220 degrees C. The i.r. spectrum of L-pyroglutamic acid varies in a manner dependent upon the matrix material and shows considerable change as the temperature of the mixtures is increased. The differences in the spectrum at elevated temperatures are explained in terms of a chemical reaction between hydroxyl groups in the matrix and the carboxylic acid. The i.r. spectra of trimethylsilyl derivatives of L-pyroglutamic acid and aluminum pyroglutamate were also measured to assist the understanding of spectra and interpretation of the spectral changes dependent upon increasing temperature.

Topics: Aluminum Oxide; Aluminum Silicates; Amino Acids; Bentonite; Clay; Hot Temperature; Kaolin; Magnesium Compounds; Minerals; Pyrrolidonecarboxylic Acid; Silicon Compounds; Silicon Dioxide; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman

The quantitative mineralogical analysis of small samples (less than 20 mg) of china clay has been investigated using x ray diffractometry to determine kaolinite, mica, quartz, and feldspar. A method has been developed and applied to the quantitative analysis of airborne dust samples and of other small discrete samples. Determinations were made either on samples after collection on a membrane filter or on samples after deposition from aqueous suspension on to a silver substrate. Quantitative analysis was hindered by preferred orientation of the kaolinite and of the mica particles that occurs when using these methods of specimen preparation. Quartz and feldspar were determined direct from prepared calibration graphs. Preferred orientation of the mica particles leads to serious interference with the most sensitive quartz x ray diffraction peak which, if not recognised, will result in an overestimation of the quartz content. Kaolinite and mica were determined from the ratio of their most intense x ray diffraction peak areas to overcome the preferred orientation effects observed for these two minerals. During the investigation, the opportunity arose for comparative measurements of quartz contents of airborne dust samples with the Occupational Medicine and Hygiene Laboratories of the Health and Safety Executive. The mass of specimen examined varied between 0.8 mg and 20 mg and the quartz contents varied between 0.1% and 1.2%. The comparative results were in good agreement.

Topics: Air Pollutants, Occupational; Aluminum Silicates; Kaolin; Particle Size; Potassium; Potassium Compounds; Quartz; X-Ray Diffraction

Topics: Aluminum Silicates; Asbestos; Beryllium; Humans; Kaolin; Lung; Lung Neoplasms; Pathology; Pneumoconiosis; Talc